Sintering machine



M. L. COVER SINTERING MACHINE Aug. 4, 1953 3 Sheets-Sheet l Filed Jan. 2, 1948 x .m D V n M y Ey NN\ S S 3 N u n .i n n R J R mmmmmwwmmwwwm www wwu mv wn a c wwmmmmmmww -W -W w nn nu un I l u mfmmmmmm mmmwww mmm mmm m v" m 3 "nu 00u n Hu b I u 1 n m UDMMMMMMMMMU MH www M ann un. una uw H nl u l n 2 nu un una nu" u H H u H n A onwmwwmwwwm www Lw- 1w- M mmmmwmmwwwww mm mmm m avlJi Mmmwwwwmmmmm uwH HMH M Uno un" nu un Hw l u l u w Y mv WWMMMWMWM www in.H HMH M ou Aug. 4, 1953 M. 1 covER SINTERING MACHINE 3 Sheets-Sheet 2 Filed Jan. 2, 1948 INVINTOR.

MARTIN L COVER ylffokNEY.

Aug. 4, 1953 M. L.. COVER SINTERING MACHINE 3 Sheets-Sheet 5 JNVENToR. MARTIN L. COVER.

Filed Jan. 2, 1948 Patented Aug. 4, 1953 SINTERING MACHINE Martiny L. (lovers Allen Park, Mich., assigner to National Steel Gorpoltiont a corporation of Delaware Application January 2, 1948, Serial No. 44

(Cl. lwli) The present invention relates Ytoimprcvenents in sintering machines of the type adapted to sinter a charge including metal bearing material and combustion supporting material to `eeot agglomeration or agglomeration and atleast partial reduction of the metal bearing material;

Relatively line iron bearing material, such as fine iron ore, ue dust, and the like, cannot be used in furnaces to produce iron andv steel. In order to utilise` such ne materials in a furnace it is necessary to sintertl'le` fine particles to form agglomeraties. At times, it is desirable to sinter. for example, iron ore containing relatively large amounts of sulphur beth to reduce'- the sulphur content and to agglomerate: the particles. The sintering charge also mcludcs sa# cient combustion supporting material, such; as sulphur or carbon, to burn andfgenerate heat to effect agglomeration. Generally, the mettermi to be sintered includes both small particles commonly designated as nes" and relativey `larger particles which are referred to. as aggregates to permit the passage of air 1through theV charge to support combustion.

The present invention will be cl'escriiseiiV more particularly in connection with the sinterlsng of charges. containing iron bearing materials such as iron ore fines, dry nue dust, wet flue dustrmill scale, and the like and containing combustion supporting materials such as carbon particles present inthe flue dust, coke breeze, and the like. It is to be understood that the present invention is not limited to the sntering efY any particular metal bearing materiel Yor mixtures of such materials.

The various ingredients of the charge. are mixed and continuously deposited ina uniform layer upon the moving pallets or' gratas: oil' the sintering machine. A well known type of sirlterl ing machine includes upper rails which support moving pallets carrying the charge from themed or entry end to the discharge end of the machine. As the pallets move along the upper' rails the charge is deposited in a layer ontoy the pallets and the particles of combustion'supporh ing material are then ignited in a zotte at the upper surface of the layer. The pallets' thenA pass above the series of Wind boxes produce a downdraft throughthe charge tri-'propagate combustion gradually downwardlythrough the material to generate sufficient heat te agglomerate the particles of iron bowing-material. At the discharge end of the machine, the pallets are emptied and then moved andurgect dic-rivis-i wardly and back along the lower rail" means te the entryend of themachine where there is a power-actuated sprocket means that raises the pallets back up and `onto the upper rails and pushes the `pallets along these upper rails. A Sintes-'mg machine of this type is usually large, the parts are made heavy to withstand the heat and abrasive conditions and is operated substantiaily continuously. A sintering machine may. for example, produce from 1,000 t0 1,200 tons of sinter ina 2li-hour day.

In actual practice, it is impossible to set up and operatesuch .a machine so that the pallets will move properly along the rails. The pallets crowd. toward one side or the other of the rails and, in addition, the pallets assume a biased position on the rails: all of which causes excessive abrasion and wearing away of the parts and at times causes the pallets to jerk as a re- Sult of the binding of the parts. As a consed quence, the' machine `must be repaired quite often and maintenance costs are high. Further,l when the pallets do not move smoothly, proper sintering may not be enacted. Various theories have been advanced as to why the pallets will not move along the rails properly and modifications have-beenimade in such machines in accordance with these theories, but these modifications have not been the answer to the problem. Consequently, the cost of maintaining and operating these machines has been quite high and the industry is stiilseeking some way of effecting proper operation of these machines. Apparently, there are a number of factors all contributing more or less te this canting andv crowding of the pallets' and it is believed that these have not been taken into consideration by the above mentioned previous theories. One factor is that itis necessary to provide large tolerances for ther moving and interfitting parts to prevent f excessive abrasion of the parts. There are fairltr large quantities of-ne abrasive dust around such machines and the parts are subjected t0 widely different temperature ranges. If the parts fitted tightlytogether, the parts would more quickly wear away and would tend to bind. Another factor contributing to improper movement and ri'onaligninent of the pallets is that there is a long column of heavy pallets extending along the rails. The length of these pallets is considerably less than their width s0 that they are unstable. A periect balance of forces would have to maintained to keep such a column of unstable palletsv in perfect balance or alignment on the rails. In practice, it is impossible tonraintein such a perfect baance that the pallets do not crowd toward one side of the rails. An additional factor contributing to misalignment of the pallets is the fact that the parts become worn relatively quickly. As a result of these and possibly other factors, sintering machine pallets have, in practice heretofore, moved improperly along the rails. This improper movement has included first, crowding of the pallets toward one side or the other of the rails and second, twisting or canting of the pallets on the rails so that the pallets do not extend normal to the rails, that is, the pallets are not properly aligned on the rails. These effects are accumulative with one increasing the other. Crowding of the pallets soon becomes excessive and the pallets are jerked along the rails instead of being moved smoothly and uniformly along the rails. Consequently, shut-downs and repairs are frequent and excessive and the machine does not function at its highest efficiency.

In the past and in accordance with some of the theories as to why the pallets did not move properly along the rails, attempts have been made to shift one sprocket relative to the other at the time of initial assembly to compensate for the subsequent twist in the sprocket shaft when loaded so that the sprocket teeth would be in alignment during operation of the machine. Such attempts have stemmed from the thought that misalignment of the pallets was possibly caused by twisting of the sprocket shaft with consequent misalignment of the sprockets and the pallets. Although twisting of the shaft may or may not be one factor contributing to improper movement of the pallets along the rails, such shifting of the sprockets has not proved to be the answer to the problem. Possibly. one reason is that it is impossible to foretell how much twist will take place. Another and possibly the correct reason is that when attempting to balance a long column of unstable pallets, the chances are that the column of pallets will shift or tilt one way or the other and it is impossible to foretell which direction the pallets will tend to tilt.

Accordingly, it is an object of the present invention to provide a sintering machine so constructed and arranged as to eliminate objectionable misalignment of the pallets.

Another object of the present invention is to provide a sintering machine adapted to effect proper balancing of the column of pallets moving along the upper and lower rails.

It is also an object of the present invention to prevent objectionable crowding of the pallets of a sintering machine toward one side or the other of the rails.

Another object of the present invention is to provide a sintering machine adapted to readily compensate for wear and abrasion of the parts.

It is also an object of the present invention to provide a sintering machine adapted to compensate for any twisting of the sprocket shaft which may take place under differing conditions and at different periods.

A further object of the present invention is to provide a sintering machine which can be continuously operated with fewer breakdowns and less frequent and extensive repairs.

In accordance with the present invention. the sprocket means for lifting the pallets from the lower rails up onto the upper rails and for pushing the pallets along the upper rails is so constructed and arranged that the pallets can be properly positioned and aligned on the machine at any period during its life so that the pallets will not unduly crowd toward one side or the other and so that the pallets will not assume an objectionable biased position. The pallets can be and are so balanced that they move properly along the rails without objectionable crowding or binding not only when the machine is first assembled, but compensations can be made to maintain this balance at any time to compensate for Wear and abrasion. Further, the sprocket means can be readily adjusted to cornpensate for twisting, if any, of the shaft. By means of the present invention, it is now possible for the first time to operate a sintering machine with the pallets moving along the rails in such a manner that there is no objectionable crowding or canting of the pallets which causes excessive wear and abrasion.

These and other objects and advantages will become more readily apparent from the following detailed description, taken in connection with the accompanying drawings, in which:

Figure 1 is a side view, partially in section, of sintering apparatus from which some of the parts have been removed to more clearly show the essential portions of the apparatus;

Figure 2 is a fragmentary, enlarged plan view, partially in section, of the apparatus of Figure 1;

Figure 3 is an enlarged fragmentary, sectional view taken along line 3 3 of Figure 2 and showing one of the sprockets;

Figure 4 is an enlarged fragmentary, sectional view taken along line 4-4 of Figure 2 showing the other sprocket;

Figure 5 is an enlarged fragmentary view partially in section of a portion of the sprocket of Figure 3;

Figure 6 is an elevational view illustrating a modification ofthe present invention;

Figure 7 is an enlarged fragmentary, sectional view taken along line 'i--T of Figure 6;

Figure 8 is an enlarged fragmentary, sectional view taken along line 8-8 of Figure 6;

Figure 9 is an elevational view of a different embodiment of the present invention;

Figure 10 is an enlarged fragmentary, sectional view taken along line Ill- Ill of Figure 9;

Figure 11 is an enlarged fragmentary, sectional View taken along line I i-I l of Figure 9;

Figure 12 is an enlarged fragmentary, sectional view taken along line |2--l2 of Figure 9; and

Figure 13 is an enlarged fragmentary view of a portion of the sprocket of Figure 9 showing the sprocket tooth portions adjusted to a different position.

Referring to the drawings and more particularly to Figures 1 and 2 which show a sintering machine of the type with which the present invention is concerned, the apparatus includes a pair of upper rails 20 and 2l mounted on crossmembers 22 supported by the machine framework 23. The rails 2B and 2l extend from the feed or loading end 24 of the machine to the discharge end 25 of the machine. The framework 23 also supports a pair of lower return rails 21 and 28 and these lower rails are inclined downwardly at the entry end 24 for reasons more fully hereinafter set forth. A plurality of pallets 29 are mounted on the upper and lower rails and each pallet 29 has a pair of rollers 30 at each side which ride on the corresponding rails. At the discharge end 25 of the machine there are two pairs of spaced, arcuate rails 3| for guiding the pallets 29 from the upper rails down onto the lower rails 21 and 28. At the entry end 24 teeth 43 or 41 are adjusted equal amounts in an arc about the axis of shaft 32 relative to the rotatable support which in this embodiment includes the body portion 42 or 46 mounted on shaft 32.

When the pallets on the upper and lower rails assume the biased position indicated by lines 59 and S2, the sprocket teeth 43 and 41 are adjusted as shown in Figures 3 and 4. Assuming the teeth 43 and 41 are in alignment with the pallets biased as described, all of the teeth 43 are adjusted in a counterclockwise direction to push ahead the left-hand sides of the pallets 29 on the upper rails 29 and 2|. The teeth 43, for example, in one sintering machine, were positioned so that the leading edge of each tooth 43 was about 1*/2 inches ahead of the leading edge of the corresponding tooth 41. This adjustment of the teeth 43 did prevent objectionable crowding of the pallets on the upper rails toward the lefthand rail but did not prevent objectionable crowding toward the left-hand rail 21 by the pallets 29 on the lower rails 21 and 28. In this particular installation it was necessary to adjust the teeth 41 in a clockwise direction so that the trailing edge of each tooth was in effect moved about 1%/2 inches relative to the corresponding tooth 43. It will be noted in Figures 3 and 4 that the teeth 43 and 41 have been adjusted so as to move the pallets slightly beyond the normal posif tion to counteract or overcome the tendency of the pallets 29 to crowd toward the left. The necessity of adjusting the teeth 41 apparently arises from the fact that the pallets on the lower rails 21 and '28 are urged downwardly and toward :s

the sprockets and it is necessary to hold back the left-hand sides 45 of these pallets. It will be noted by comparing Figures 3 and 4 that as the sprocket teeth engage the pallets to lift them, the leading edge of tooth 43 engages the forward side of the recess 44 and the trailing edge of tooth 41 engages the rearward side of recess 48 to push forwardly and rearwardly the corresponding sides of the pallets. As shown in Figure 4, the right-hand sides of the pallets on the lower rails tend to push ahead. As the pallets are raised by the sprockets. the right-hand side moves downwardly until the tooth 41 engages the forward side of recess 48. When the pallets reach the top of the sprockets each tooth 43 and 41 engages the forward side oi the corresponding recex. The leading edge of tooth 43 is ahead of the leading edge of tooth 41 so that the pallets 29 on the upper rails are biased a slight amount in an opposite direction from that originally described and indicated by lines 59 and 62. This biasing or canting of the pallets effect ed by adjustment of the teeth prevents objectionable crowding of the pallets toward the left-hand rails and does not cause objectionable crowding toward the right-hand rails. If the teeth are adjusted too far objectionable crowding toward the right-hand rails may take place.

Referring more particularly to Figures 6, 7 and 8 which show a different sprocket 1I that can be substituted for sprockets 39 and 40, the sprocket 1I includes a body portion 12 containing keyways 13 for connecting it to shaft 32 and has an outer rim 15 on which is movably mounted a ring 16 having formed thereon a plurality of sprocket teeth 11. The ring 16 includes a plurality of arcuate slots 18. A bolt 19 extends through each slot 18 and a corresponding hole 89 in rim 15 with a nut 8| threaded onto its inner end. The nuts BI can be loosened and the 8, ring 16 and teeth 11 adjusted in an are about the axis of the shaft. The nuts 8| can then be tightened to lock the ring 16 and teeth 11 in the adjusted position. The method of adjusting the teeth of sprocket 1I is the same as the method of adjusting the teeth of sprockets 39 and 40. The sprocket 1i has an important advantage over the type of sprocket 39 or 48 in that with sprocket 1I one adjustment simultaneously adjusts al1 of the teeth and it is not necessary to individually adjust each tooth.

When the sprockets are constructed as shown in Figure 5 or in Figure 6, it is preferable that both sprockets be constructed so that the teeth can be adjusted, although it is to be understood `that one of the sprockets may be constructed in the customary manner with fixed teeth. With the last mentioned type of sprockets it is necessary to adjust the adjustable teeth twice the distance, which at times may be undesirable.

Referring more particularly to Figures 9 to 13, inclusive, which illustrate another type of sprocket 82 that can be substituted for sprockets 39 and 40, the sprocket 82 includes a body portion 83 having an outer rim portion 84. Two rings 85 and 86 are movably mounted on rim portion 84. Ring 85 includes integral leading tooth portions 81 and ring 86 includes integral trailing tooth portions 88. Each tooth portion 81 forms with its corresponding tooth portion 8B one composite tooth 39 adapted to engage the corresponding recess of the pallet 29. The rings B5 and 86 include elongated slots 9G and 9i, respectively. A bolt 92 extends through each pair of these slots 98 and 9| and a hole 93 in rim 35. A nut 94 is threaded onto one end of each bolt 92. The nuts 94 can be loosened and the rings 85 and 8E turned in the same direction, or in opposite directions on rim 84, or one ring 85 or 8S can be turned without turning the other ring to adjust the leading and trailing portions of teeth 89 relative to each other. When the sprocket of Figure 9 is used, both sprockets are preferably made alike to obtain full advantage of this construction.

Assuming that the pallets are biased as indicated by the lines 59 and 62 and that each of sprockets 39 and 40 has been replaced by a sprocket 82, then the ring 85 of the left-hand sprocket (same side as sprocket 39) is turned in a counterclockwise direction and locked in place to push the left-hand sides 45 of the pallets on the upper rails ahead. The ring 85 of the right-hand sprocket is adjusted in a clockwise direction to hold back the right-hand sides 49 of the pallets on the lower rails. Thus, by adjusting only the leading edge portions 81 of the teeth of one sprocket and the trailing edge portions 88 Iof the other sprocket, the same adjustment is obtained as has been described in connection with the other sprockets. This type of adjustment separates the tooth portions 81 and 88 and in effect increases the thickness of tooth 89. The tooth portions should not be so widely spread apart that the tooth 89 is as wide as the corresponding recess as it is desirable to have the sprocket tooth 89 smaller than the recess, as are the teeth of the other sprockets, to reduce wear. Normally, the sprocket teeth are considerably smaller than the recess which provides sufficient space for adjustment. Where the amount of adjustment necessary is quite large, both tooth portions may be adjusted in the same direction with one tooth portion being adjusted a greater amount than the other, if desirable.

. made.

sprockets adjusted as described, the nonadjusted trailingr tooth portions B8 of the left-hand sprocket or the leading edge portions 81 of the righthand sprocket can also be adjusted to control more accurately the amount that the pallets are biased in the opposite direction. Another important advantage obtainable with sprockets 82 is that a greater variety of adjustments can be For example, if the pallets on the upper rails are crowding toward one side and the pallets on the lower rails are not crowding toward `one side in an objectionable manner, then the leading tooth portions on the side toward which the pallets crowd on the upper rails can be adjusted ahead to overcome this condition without disturbing the trailing tooth portions of either Y sprocket.

After the sprockets have been adjusted to prevent objectionable crowding of the pallets, the pallets will move smoothly along the rails and abrasion and wearing away of the parts is greatly reduced. This increases the life of the parts and reduces the costof repairs and the time required for maintaining the machine in proper order. At least at times, it will be necessary to make subsequent adjustments of the sprocket teeth as a result of the wearing away of the parts. These subsequent adjustments are, in addition to the adjustment, required to have a newly assembled machine function properly. These adjustments of the sprocket teeth after first assembling the machine are required as. it is impossible to forecast in what direction the pallets will crowd. It is necessary to assemble the sintering machine and operate it to determine that side toward which the pallets crowd and to determine what position the pallets `will assume. The action of the pallets is not accurately predictable. Although Wear may increase objectionable crowding of the pallets, it is only a partial cause of crowding and objectionable crowding does take place before there is any wear on the parts.

It is to be understood that the sprockets need not be constructed exactly the same. For example, one sprocket may be constructed like sprocket 82 and the other sprocket constructed like either of .the other sprockets. In each of the embodiments shown and described, at least the leading or trailing portions of the teeth of one sprocket are not in alignment. least corresponding portions of the teeth of each pair are not in alignment and this misalignment prevents objectionable crowding of the pallets.

I claim:

1. In apparatus for continuously sintering metal bearing material, the combination oomprising a plurality of `pallets for supporting such material, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lowerv rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, power-actuated sprocket means at one end of the rail means and rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means through an arc to the upper rail means and to push the lifted pallets along the upper rail means, said sprocket means including a rotatable support for the sprocket teeth rotatable on said axis, two sets of Thus, at

lO transversely spaced apart teeth arranged about the periphery of the support and adapted to engage opposite side portions of the pallets, the teeth of at least one set being movable relative i to the support in an arc about said axis, and releasable locking means operable to lock the movable teeth in a xed predetermined position on the support and operable to permit such movement of the movable teeth relative to said support.

2. In apparatus for continuously sintering metal bearing material, the combination comprising a plurality of pallets for supporting such material, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, power-actuated sprocket means at one end oi' the rail means and rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means through an arc to the upper rail means and to push the lifted pallets along the upper rail means, said sprocket means including a rotatable support for the sprocket teeth rotatable on said axis, two sets of transversely spaced apart teeth arranged about the periphery of the support and adapted to engage opposite side portions of the pallets, the teeth oi each set being movable relative tothe teeth of the other set and to the support in an arc about said axis, and releasable locking means operable to lock the movable teeth in a fixed predetermined position on the support and operable to permit such movement of the movable teeth relative to said support.

3. In apparatus for continuously sintering metal bearing material, the combination comprisinga plurality of pallets for supporting such material, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, power-actuated sprocket means at one end of the rail means and rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means through an arc to the upper rail means and to push the lifted pallets along the upper rail means, said sprocket means including a rotatable support for the sprocket teeth rotatable on said axis. two sets of transversely spaced apart teeth arranged about the periphery of the support and adapted to engage opposite side portions of the pallets, each tooth of at least one set being formed of sepl arate leading and trailing portions and the leading tooth portions of said one set of teeth being connected together and movable relative to the support in an arc about said axis, and releasable locking means operable to lock the movable leading tooth portions in a iixed predetermined positionon the support and operable to permit such movement of the movable leading tooth portions relative to said support.

4. In apparatus for continuously sintering metal bearing material, the combination comprising a plurality of pallets for supporting such material, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, power-actuated sprocket means at one end ofthe rail means and rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means through an are to the upper rail means and to push the lifted pallets along the upper rail means, said sprocket means including a rotatable support for the sprocket teeth rotatable on said axis, two sets of transversely spaced apart teeth arranged about the periphery of the support and adapted to engage opposite side portions of the pallets, the teeth of each set being independently movable relative to the teeth of the other set and to the support in an are about said axis, and releasable locking means operable to lock the movable teeth in a fixed predetermined position on the support and operable to permit movement of the movable teeth relative to said support.

5. In apparatus for continuously sintering metal bearing material, the combination comprising a plurality of pallets for supporting such material, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, power-actuated sprocket means at one end of the rail means and rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means through an are to the upper rail means and to push the lifted pallets along the upper rail means, said sprocket means including a rotatable support for the sprocket teeth rotatable on said axis, two sets of transversely spaced apart teeth arranged about the periphery of the support and adapted to engage opposite side portions of the pallets, the teeth of I each set being movable in unison relative to the teeth of the other set and to the support in an are about said axis, and releasable locking means operable to lock the movable teeth in a fixed predetermined position on the support and operable to permit movement of the movable teeth relative to said support.

6. In apparatus for continuously sntering metal bearing material, the combination comprising a plurality of pallets for supporting such material, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, power-actuated sprocket means at one end of the rail means and rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means through an arc to the upper rail means and to push the lifted pallets along the upper rail means, said sprocket means including a rotatable support for the sprocket teeth rotatable on said axis, two sets of transversely spaced apart teeth arranged about the periphery of the support and adapted to engage opposite side portions of the pallets, each tooth of at least one set being formed of separate leading and trailing portions and the leading tooth portions of said one set of teeth being connected together and movable relative to the support in an arc about said axis and the trailing tooth portions being connected together and independently movable relative to the support in an arc about said axis, and releasable locking means operable to lock the movable tooth portions in a fixed predetermined position on the support and operable to permit such movement of the movable tooth portions relative to said support.

'7. In apparatus for continuously sintering metal bearing material, the combina/G1011 60mprising a plurality of pallets for supporting such material, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, power-actuated sprocket means at one end of the rail means and rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means through an arc to the upper rail means and to push the lifted pallets along the upper rail means, said sprocket means including a rotatable support for the sprocket 'teeth rotatable on said axis, two sets of transversely spaced apart teeth arranged about the periphery of the support and adapted to engage opposite side portions of the pallets, ring means supporting at least one set of teeth on the rotatable support and being movable back and forth relative to the support in an arc about said axis, and releasable locking means operable to lock the ring means in a fixed predetermined position on the support and operable to permit such movement of the ring means relative to said support.

8. In apparatus for continuously sintering metal bearing material, the combination comprising a plurality of pallets for supporting such material, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, power-actuated sprocket means at one end of the rail means and rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means through an arc to the upper rail means and to push the lifted pallets along the upper rail means. said sprocket means including a rotatable support for the sprocket teeth rotatable on said axis, two sets of transversely spaced apart teeth arranged about the periphery of the support and adapted to engage opposite side portions of the pallets, separate ring means supporting each set of teeth on the rotatable support and each ring means being movable back and forth relative to the support in an arc about said axis, and releasable locking means operable to lock the ring means in a xed pre-- determined position on the support and operable to permit such movement of the ring means relative to said support.

9. In apparatus for continuously sintering metal bearing material, the combination comprising a plurality of pallets for supporting such material, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, power-actuated sprocket means at one end of the rail means and rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means through an arc to the upper rail means and to push the lifted pallets along the upper rail means, said sprocket means including a rotatable support for the sprocket teeth rotatable on said axis, two sets oi transversely spaced apart teeth arranged about the periphery of the support and adapted to engage opposite side portions of the pallets, ring means including two ring members suD- porting a set of the teeth on the rotatable support, the supported set of teeth being formed of separate leading and trailing portions and one ring member carrying the leading tooth portions and the other ring member carrying the trailing tooth portions and both ring members being movable relative to `the support and each other in an arc about said axis, and releasable looking means operable to lock the ring members in a Iixed predetermined position on the support and relleasable to permit such movement of the ring members relative to said support.

10.111 apparatus for continuously sinterng metal bearing material, vthe combination comprising a plurality of pallets for supporting such material, upper rail means supporting a plurality ef pallets for movement therealong while supporting the material being sintered, lower rail means supporting a plurality oi empty pallets for return movement therealong in an opposite direction, power-actuated Sprocket means at one end of the rail means and rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means through an arc to the upper rail means and to push the lifted pallets along the upper rail means, said sprocket means including a rotatable support for the sprocket teeth rotatable on said axis, two sets of transversely spaced apart teeth arranged about the periphery of the support and adapted to engage opposite side portions of the pallets, the teeth of each set being formed of separate leading and trailing portions, separate ring means supporting each set of teeth on the rotatable support, each ring means including two ring members, each ring member being movable relative to the support in an arc about said axis, one ring member of each ring means carrying the leading portions of the teeth and the second ring member carrying the trailing portions of the teeth of the corresponding set, and releasq able locking means operable to look the ring members of each ring means in a xed predetermined position on the support and operable to permit such movement of the ring members relative to said support.

l1. In apparatus for continuously sintering metal bearing material, the combination comprising a plurality of pallets for supporting suchl material, each pallet including a recess adjacent each side, upper rail means supporting a plurality of pallets for movement therealong While supporting the material being sintered, lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction under the influence of gravity, and rotatable power-actuated sprocket means at one end of the rail means, said sprocket means including a plurality of pairs of spaced apart teeth arranged about its periphery for engaging the recesses of the pallets and successively raising the pallets from the lower rail means to the upper rail means and pushing the pallets along the upper rail means upon rotation of said sprocket means, said teeth being thinner than the recesses and one tooth of each pair of teeth being positioned ahead of the other tooth of said pair.

12. In apparatus for continuously sintering metal bearing material, the combination comprising a plurality of pallets for supporting such material, each pallet including a recess adjacent each side, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction under the influence of gravity, and rotatable power-actuated sprocket means at one end or the nail means, said sprocket means including a plurality of pairs of spaced apart teeth arranged about its periphery OI engaging the recesses of the pallets and `successively raisins the pallets from the lower rail means to upper rali means and pushing the pallets along the upper rail means upon rotation or .said Splkt means, A'said teeth being thinner than 'the recesses and one tooth of each pair of teeth having iat least its trailing edge positioned ahead of the trailing edge or the other tooth of said pair.

i3. In apparatus for continuously sintering `metal bearing material, the combination comprlslng a plurality of pallets for supporting such material, each pallet including a recess adjacent each side, upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered, lower rail means supporting a. plurality oi empty pallets for return movement therealong in an opposite direction under the inuence of gravity, and rotatable power-actuated sprocket means at one end of the rail means, said sprocket means including a plurality of pairs of spaced apart teeth arranged about its periphery for engaging the recesses of the pallets and successively raising the pallets from the lower rail means to the upper rail means and pushing the pallets along the upper rail means upon rotation of said sprocket means, said teeth being thinner than the recesses and at least one tooth of each pair being movably supported for movement relative to the other tooth of the pair in an arc about said axis.

14. In apparatus for continuously sintering metal bearing material, the combination comprising, a plurality of pallets for supporting the material while being sintered, rail means including upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered and lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, and power-actuated sprocket means at one end of the rail means and rotatably about a horizontal transverse axis to lift the returning pallets from the lower rail means through an arc to the upper rail means and to push the lifted pallet along the upper rail means, said sprocket means including a pair of rotatable sprockets, each sprocket including a body and a set of sprocket teeth arranged about the periphery of the body, the two sets of sprocket teeth being adapted to engage opposite side p0rtions of the pallets, the pallets tending to cant and crowd toward one side of the rail means and the teeth of at least one set being adjustable relative to the corresponding sprocket body 1n an arc about said axis to reduce the canting and crowding of the pallets, releasable locking means operable to lock the movable teeth in a fixed position on the corresponding bodies and releasable to permit such movement of the teeth relative to the corresponding body.

15. In combination with a sintering machine for continuously sintering metal bearing material, the sintering machine including elongated upper rail means supporting a plurality of pallets for movement therealong while supporting the material being sintered and elongated lower rail means supporting a plurality of empty pallets for return movement therealong in an opposite direction, the pallets tending to cant and crowd toward one side of the rail means; power actuated sprocket means at one end of the rail means including a. pair of sprockets each lncluding a. body and a. set of sprocket teeth arranged about the periphery of the body, the sprockets being rotatable about a horizontal transverse axis to lift the returning pallets from the lower rail means up through an arc onto the upper rail means and to push the lifted pallets `along the upper rail means with the two sets of sprockets being adapted to engage opposite side portions of the pallets as the pallets are moved from the lower up onto the upper rail means, means connecting at least one set of the 'teeth to the corresponding sprocket body and being constructed and arranged to permit adjusting movement of the one set of teeth rela tive to the corresponding sprocked body and relative to the other set of teeth in an arc about said axis to reduce canting and crowding of the References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 588,577 Humphreys Aug. 24, 1897 717,976 Dodge Jan. 6, 1903 1,764,696 Shallock June 17, 1930 1,934,986 Magee Nov. 14, 1933 2,382,740 Noffsinger Aug. 14, 1945, 

